东准噶尔老爷庙地区早石炭世黑山头组火山岩地质、地球化学特征及构造环境分析

Geological、Geochemistry Significance and Tectonic Environment of the Early Carboniferous Heishantou Formation Volcanic Rock in Laoyemiao Area,Eastern Junggar

东准噶尔东部老爷庙地区黑山头组火山岩由玄武岩(少)+安山岩+英安岩+流纹岩组成,属高钾钙碱性-钾玄岩系列,流纹岩LA-ICP-MS锆石U-Pb加权平均年龄为(330.7±7.4)Ma。富集大粒子亲石元素Rb,K,Ba,Th,亏损Nb,Ta,P,Ti,弱负Eu异常,稀土分布型式及微量元素特征与安第斯型相似,形成于活动大陆边缘,岩浆来源于俯冲板片部分熔融改造后的富集地幔楔。表明卡拉麦里洋在早石炭世仍向北俯冲消减。

The Laoyemiao area is located in the eastern part of East Junggar, developing a set of continental-acidic volcanic rocks.The combination of lithology is basalt (less)+ andesite + dacite + rhyolite, which belongs to the series of high-potassium-calcium-alkaline-potassium rocks,LA-ICP-MS zircon U-Pb obtained rhyolite age of (330.7±7.4)Ma, Volcanic rocks are enriched with large particles of lithophile elements Rb, K, Ba, Th, loss of Nb, Ta, P, Ti, weak negative Eu anomaly, and the characteristics of rare earth partitioning and trace elements are similar to the Andean type. Formed on the edge of the active continent,the magma is derived from the partially melted and reconstructed slow wedge of the subduction plate.It indicates that the Kalamaili Ocean still has a northward subduction in the Early Carboniferous.